(define (let*? expr) (tagged-list? expr 'let*)) 
(define (let*-body expr) (caddr expr)) 
(define (let*-inits expr) (cadr expr)) 
(define (let*->nested-lets expr) 
  (let ((inits (let*-inits expr)) 
        (body (let*-body expr))) 
    (define (make-lets exprs) 
      (if (null? exprs) 
        body 
        (list 'let (list (car exprs)) (make-lets (cdr exprs))))) 
    (make-lets inits))) 
